The present disclosure relates to toilet flush valves configured to impart multiple flush types (e.g. dual flush) from a toilet tank into a toilet bowl. For purposes of discussion, a toilet tank typically has a flush valve system that is forced opened and remains opened until a predetermined volume of liquid flows from the tank into the toilet bowl through the flush valve system. Liquid is supplied to the toilet tank through a fill valve from a liquid supply line to the toilet tank. In practice, the fill valve opens when the fluid level in the tank falls below a predetermined liquid level.
Flush valve assemblies typically include a flush valve, a float and an actuation mechanism. The actuation mechanism causes the flush valve to open and release liquids stored in tank into the toilet bowl and close when the float reaches a predetermined liquid level in the tank. For a dual flush valve, the toilet bowl may be refilled with liquids during the time the fill valve fills the toilet tank. The predetermined volume of liquid that refills the toilet bowl is sufficient to seal off the trap way of the bowl. In practice this predetermined volume amount may be defined as ratio of the total liquid volume supplied by the fill valve during a particular flush cycle. The fill valve feeds the liquids and feeds them to the tank bowl.
Toilets that can impart dual flushes have been found to be particularly advantageous in several situations. Specifically, prior to initiating a flush, a user may choose between a large flush water volume for solid waste (e.g. a full flush) or a smaller flush water volume for liquid waste (e.g. a partial flush). This may be done via a switch, button or the like on the actuation mechanism.
In general, dual flush valves (shown in FIG. 2) may be equipped with a flush volume controlling device associated with a flush volume, a drain opening lock, and full and partial flush control devices in order to maximize the volume of respective full and partial flushes. Full and partial flush control devices are typically adjustable to maximize respective flush volumes. Typically, a drain opening controls water inside of the reservoir that holds the full flush float. The size of the reservoir drain opening is controlled by the window lock that ultimately determines the full flush volume. In practice, OEM toilet manufacturers may preset the window lock position for their respective toilet models to comply with code such as watersense.
However, if the end user is able to alter the window lock setting, such alteration may violate the code due to the approved flush volume change. Accordingly, there is a need to resolve this problem so that end users are prevented from altering window lock settings.